package mylinkedlist;

import mysinglelist.MySingLeList;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: lenovo
 * Date: 2024-07-17
 * Time: 17:39
 */
public class MyLinkedList {
    static class ListNode{
        private int val;
        private ListNode prev;
        private ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }
    ListNode head;
    ListNode last;

        //头插法
        public void addFirst(int data){
            ListNode node = new ListNode(data);
            if(head == null){
                head = node;
                last = node;
            }else{
                node.next = head;
                head.prev = node;
                head = node;
            }
        }
        //尾插法
        public void addLast(int data){
            ListNode node = new ListNode(data);
            if(head == null){
                head = node;
                last = node;
            }else{
                last.next = node;
                node.prev = last;
                last = node;
            }
        }
        //任意位置插入,第一个数据节点为0号下标
        public void addIndex(int pos,int data){
            ListNode node = new ListNode(data);
            ListNode cur = head;
            if(pos == 0){
                addFirst(data);
            }else if(pos == this.size()){
                addLast(data);
            }else if(pos < 0 || pos > this.size()){
                System.out.println("插入位置错误！");
            }else{
                for (int i = 0; i < pos; i++) {
                    cur = cur.next;
                }
                cur.prev.next = node;
                node.prev = cur.prev;
                node.next = cur;
                cur.prev = node;
            }

        }
        //查找是否包含关键字key是否在单链表当中
        public boolean contains(int key){
            ListNode tmp = this.head;
            while(!(tmp == null)){
                if(tmp.val == key){
                    return true;
                }
            }
            return false;
        }
        //删除第一次出现关键字为key的节点
        public void remove(int key){
            ListNode cur = head;
            while(cur != null){
                if(cur.val == key){
                    if(cur == head){
                        head = head.next;
                        if(head != null){
                            head.prev =null;
                        }else{
                            last = null;
                        }
                        return;
                    }else if(cur == last){
                        last = last.prev;
                        last.next = null;
                        return;
                    }else{
                        cur.prev.next = cur.next;
                        cur.next.prev = cur.prev;
                        return;
                    }
                }else{
                    cur = cur.next;
                }
            }
            System.out.println("没有该元素！");
            return;
        }
        //删除所有值为key的节点
        public void removeAllKey(int key){
            ListNode cur = head;
            while(cur != null){
                if(cur.val == key){
                    if(cur == head){
                        head = head.next;
                        if(head != null){
                            head.prev =null;
                        }else{
                            last = null;
                        }
                    }else if(cur == last){
                        last = last.prev;
                        last.next = null;
                    }else{
                        cur.prev.next = cur.next;
                        cur.next.prev = cur.prev;
                    }
                }
                cur = cur.next;
            }
            System.out.println("没有该元素！");
            return;
        }
        //得到链表的长度
        public int size(){
            int count = 0;
            ListNode cur = head;
            while(cur != null){
                count++;
                cur = cur.next;
            }
            return count;
        }
        public void display(){
            ListNode tmp = this.head;
            while(!(tmp == null)){
                System.out.print(tmp.val+" ");
                tmp = tmp.next;
            }
        }
        public void clear(){
            ListNode cur = head;
            while(cur != null){
                ListNode curNext = cur.next;
                cur.prev = null;
                cur.next = null;
                cur = curNext;
            }
            head = null;
            last = null;
        }
}
